Although most radiation levels around baggage X-ray machines were low, six of 281 machines used to screen checked luggage violated federal radiation standards, some emitting two or three times the allowed limit, the CDC found.

Perhaps most troubling, the CDC had found what the Transportation Security Administration hadn’t noticed. The TSA and its contractors had failed to identify the machines that were emitting excessive radiation — a failure that continues to leave TSA workers and some lawmakers uneasy, especially as the agency continues to deploy hundreds of controversial radiation-emitting machines to help screen passengers.

Although the CDC report, finished in 2008, concluded that the radiation levels didn’t pose a “direct hazard” to TSA workers, it recommended that the TSA take steps to protect against excessive exposures. Health guidelines call for people to limit their exposure to radiation as much as reasonably possible.

In late November, USA TODAY requested current inspection reports for the 4,080 X-ray machines used to examine checked and carry-on bags, and for the 221 new full-body X-ray scanners. The TSA insists that all have passed radiation inspections conducted by contractors but has thus far been unwilling to release the reports.

Members of Congress are now calling on the TSA to release radiation inspection records, and one lawmaker — Rep. Ed Markey, D-Mass. — has asked for an investigation into the effectiveness of the TSA’s oversight of its X-ray machines.

The TSA’s lack of transparency troubles agency workers, according to the union that represents them.

Jill Segraves, director of TSA’s occupational safety office, said the problems identified by CDC were a result of the agency’s rapid creation in the wake of the Sept. 11, 2001, attacks. “We didn’t even have policies and procedures in place yet,” she said, noting TSA’s safety office wasn’t created until 2003.

“Now we have a much better educated workforce. They understand what to look for with these systems,” Segraves said. A different contractor now maintains the TSA’s airport equipment, she said, and every machine receives a radiation test at least annually, at installation and after maintenance issues.

TSA, Army inspect machines

Airport X-ray machines are exempt from the state radiation control inspections they would receive if installed at a local courthouse or in a non-federal office building.

The U.S. Food and Drug Administration doesn’t routinely inspect airport X-ray machines either because they are not medical devices, said FDA spokesman Dick Thompson.

That leaves the TSA responsible for inspecting its own devices.

Since 2008, the TSA has contracted with the U.S. Army Public Health Command to do additional radiation spot checks at 10-12 of the nation’s 450 commercial passenger airports each year. The added layer of scrutiny is supposed to act as a backstop to the regular inspections and monitoring done by maintenance contractors.

So far the Army radiation inspectors have checked 437 baggage X-ray machines at 34 airports selected by TSA; all had radiation emissions “well below” federal requirements, said Fran Szrom, a health physicist with the Army program.

Every year Americans are exposed to about 300 millirem of radiation from naturally occurring sources, from rocks and soil to cosmic rays, according to the Health Physics Society. The amounts of radiation emitted by properly working airport X-ray equipment is small, though some experts disagree how small.

Federal regulations require X-ray machines that screen bags to emit less than 0.5 millirem an hour. Currently, there are 221 backscatter X-ray machines to screen passengers at 39 airports. According to the TSA, each scan delivers a radiation dose of less than 0.01 millirem.

For the new backscatter X-ray full-body scanners, Army inspectors have taken radiation readings in and around 15 of the scanners at three airports: Cincinnati, Boston and Los Angeles. All of them met safety standards and delivered less than 0.005 millirem per screening, Szrom said.

Not all of the TSA’s new full-body scanners use X-rays to see through passengers’ clothing. Of 412 full-body scanners deployed so far, 191 at 30 airports use a different technology called millimeter wave, that uses electromagnetic waves instead of ionizing radiation.

Concerns remain

Despite assurances, some TSA workers don’t trust that the agency has fixed the kinds of maintenance and monitoring issues identified by the CDC, said union official Rodriguez.

Because TSA workers at airports in Boston and San Juan were troubled by what they saw as possible cancer clusters among colleagues, the TSA this year requested health hazard evaluations of their work areas to address radiation concerns, CDC records show. The CDC found nothing unusual about the number of cancer cases and determined they were likely unrelated to airport X-ray machines, the reports say.

And a TSA employee at an unidentified airport asked CDC in June to examine concerns about radiation exposures from standing near the new full-body X-ray scanners for hours a day. The CDC said it didn’t have authority to do a hazard assessment unless three or more current employees at one location made a joint request, according to a September letter from the CDC to the unnamed worker. The CDC provided the letter to USA TODAY.

Since April 2009, the Army team also has been studying the radiation doses received by TSA workers at six airports, Philadelphia, Baltimore, West Palm Beach, Memphis, Los Angeles, Portland, Ore. The report is not yet final, but Szrom said all the data shows radiation exposure is low — “well below” limits that would require workers to routinely wear radiation monitoring badges.

The backscatter machines have drawn criticism among some scientists and health experts who are concerned about subjecting thousands of travelers to even tiny doses of radiation.

Peter Rez, a physics professor at Arizona State University, also worries about the possibility of higher doses or even radiation burns if a machine malfunctions and the scanning beam stops on one part of the body. Rez, who has reviewed a patent application for the backscatter system, notes that the scanner has a fail-safe system that is supposed to shut down the X-ray beam if there’s a problem. “But we all learned this summer that fail-safe systems do fail,” Rez said, referring to the mechanical failures that resulted in the massive Gulf oil spill.

Rapiscan Systems, the company that makes the full-body backscatter X-ray scanners used by TSA, did not respond to interview requests.

The new full-body scanners have raised more concerns than the baggage X-ray machines, despite TSA and FDA assurances that they’re safe.

David Brenner, director of Columbia University‘s center for radiological research, questions whether it’s good public policy to give millions of people the backscatter scans — even if the health risk is remote.

“The radiation dose is very, very low indeed,” Brenner said. “From most individuals’ point of view, I don’t think one should have much concern about walking through these scanners.”

But as millions of scans are performed on large populations of people, Brenner said “you can be reasonably convinced a certain number of people will end up with a cancer from the radiation exposure, despite the fact the risk to the individual is very low.” Skin cancer, is the primary risk, he said.

Brenner said a few people getting cancer might be acceptable in return for air security if there weren’t an alternative technology — the millimeter wave machines — that had no known health risk. “Why use a technology where the best estimate is there will be come cancers somewhere down the line?” he asked.

TSA spokesman Kimball said the TSA competitively bids for new technology and will deploy those that meet its threat detection and safety standards. Both millimeter wave and backscatter X-rays meet those standards, he said.

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